package day06;

import java.util.Random;

/**
 * 需求：
 * 生成?位验证码（大写字母、小写字母、数字）
 */
public class VerificationCode {
    public static void main(String[] args) {
     String code = generateVeriCode(4);
        System.out.println("验证码："+code);

    }
    /** 生成验证码 */
    public static String generateVeriCode(int len){
       String code = "";
        Random rand = new Random();
       char[]chs = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p'
               ,'q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G'
               ,'H','I','J','K','L','M','N','O','P','R','S','T','U','V','W','X','Y',
               'Z','0','1','2','3','4','5','6','7','8','9'
       };
       for(int i =1;i<=len;i++){//len次
           int index = rand.nextInt(chs.length);//随机下标(0到61）
           code += chs[index];//获取随机字符并拼接到code中
       }
        return code;
    }

}
